Prospective, population-based detection of intracranial vascular malformations in adults – The Scottish Intracranial Vascular Malformation Study (SIVMS)

Background and Purpose – Intracranial vascular malformations (IVMs) are an important cause of intracranial hemorrhage, epilepsy, and long-term disability in adults. There are no published prospective, population-based studies dedicated to the detection of any type of IVM ( cavernous malformations, venous malformations, and arteriovenous malformations [AVMs] of the brain or dura). Therefore, we established the Scottish Intracranial Vascular Malformation Study (SIVMS) to monitor detection and long-term prognosis of people with IVMs. Methods – We used multiple overlapping sources of case ascertainment to identify adults ( aged greater than or equal to16 years) with a first-ever-in-a-lifetime diagnosis of any type of IVM made between January 1, 1999, and December 31, 2000, while resident in Scotland (mid-1999 adult population estimate 4 110 956). Results – Of 418 notifications to SIVMS, 190 adults (45%) were included, 181 (95%) of whom were deemed to harbor a definite IVM after review of diagnostic brain imaging and/or reports of autopsy/surgical excision pathology. The crude detection rate ( per 100 000 adults per year) was 2.27 ( 95% CI, 1.96 to 2.62) for all IVMs, 1.12 ( 95% CI, 0.90 to 1.37) for brain AVMs, 0.56 ( 95% CI, 0.41 to 0.75) for cavernous malformations, 0.43 ( 95% CI, 0.31 to 0.61) for venous malformations, and 0.16 ( 95% CI, 0.08 to 0.27) for dural AVMs. Conclusions – In addition to providing data on the public health importance and comparative epidemiology of IVMs, continuing recruitment and follow-up of this prospective, population-based cohort will provide estimates of IVM prognosis.